> ## Documentation Index > Fetch the complete documentation index at: https://docs.budgetpixel.com/llms.txt > Use this file to discover all available pages before exploring further. # Generate sound effect with Sonilo Video SFX > Sonilo video-to-sound-effect — frame-accurate Foley, ambience, impacts and action sounds synced to the visible events of an input video (up to 6 minutes). Returns the SFX track (`audio_url`, MP3 or WAV) and the video with the effects mixed in (`video_url`). Priced per second of the input video's measured duration (whole seconds, 3-second minimum) — see GET /v1/models for the rate. **Asynchronous.** Returns a job `id` (nothing is generated yet in this response). Poll [`GET /v1/audios/{id}`](/api-reference/audios/get-music-job-status) until `status` is `succeeded` — the SFX track is that response's `audio_url` and the input video with the effects mixed in is its `video_url`. Charged per second of the input video's measured duration (whole seconds, 3-second minimum; rate in `GET /v1/models`) on success only. ## OpenAPI ````yaml /openapi.yaml post /audios/sonilo-video-sfx openapi: 3.1.0 info: contact: email: support@budgetpixel.com name: BudgetPixel Support description: > The BudgetPixel developer API for programmatic image, video, music and sound-effect generation. Generation is **asynchronous**: you create a job, then poll its status until it reaches a terminal state (`succeeded` / `failed`). You are charged in credits only on success — never for failures, timeouts, or content blocked before generation. **Authentication.** All requests require an API key sent as a bearer token: Authorization: Bearer bpx_live_xxx Create and manage keys from your BudgetPixel account dashboard. The developer API is available on the **Premium** plan and above. **Pricing.** API usage is metered in credits at each model's published price (see `GET /v1/models`), and your plan's model discounts and active promotions apply to API charges exactly as they do on the web — `POST /v1/cost` quotes your discounted price. Pro and Ultra plans include a daily free-models allowance (a shared pool of free generations per day across qualified image models such as FLUX 2 Klein and Qwen-Image) that covers API requests too — the standard price applies once the day's pool is used. Other promotional free daily generations remain web/app-only. Failed generations are never charged. **Rate limits.** Requests are limited per minute: **600 requests/min per API key** and **1200 requests/min per source IP** (defaults; subject to tuning). Every response carries `X-RateLimit-Limit`, `X-RateLimit-Remaining`, and `X-RateLimit-Reset` (seconds until the window resets). Exceeding a limit returns HTTP `429` with a `Retry-After` header — wait that long before retrying. Rejected requests still count against the window, so a tight retry loop keeps you limited; back off instead. Generation jobs additionally have a per-plan concurrency cap (the same one as the web workshop), independent of these request limits. `POST /v1/uploads` also has a dedicated **60 uploads/min per account** cap (it's free/unmetered) on top of these limits. title: BudgetPixel API version: '2026-06-20' servers: - description: Production url: https://api.budgetpixel.com/v1 security: - ApiKeyAuth: [] tags: - description: Account and credit balance name: Account - description: Discover available models and pricing name: Models - description: Upload input media for image/video generation name: Uploads - description: Image job status name: Images - description: FLUX image models name: Black Forest Labs - description: SeeDream image models name: Bytedance - description: Video job status name: Videos - description: Kuaishou Kling video models name: Kling - description: SeeDance video models name: ByteDance (SeeDance) - description: Music and sound-effect job status name: Audios - description: Music generation models name: Music - description: Text-to-sound-effect models (priced per second) name: Sound Effects - description: Format conversion for images, video, and audio name: Conversions - description: Publish posts to your BudgetPixel feed name: Social - description: Content moderation — NSFW rating and CSAM detection name: Moderation - description: Content classification — music genre detection name: Classification paths: /audios/sonilo-video-sfx: post: tags: - Sound Effects summary: Generate sound effect with Sonilo Video SFX description: >- Sonilo video-to-sound-effect — frame-accurate Foley, ambience, impacts and action sounds synced to the visible events of an input video (up to 6 minutes). Returns the SFX track (`audio_url`, MP3 or WAV) and the video with the effects mixed in (`video_url`). Priced per second of the input video's measured duration (whole seconds, 3-second minimum) — see GET /v1/models for the rate. **Asynchronous.** Returns a job `id` (nothing is generated yet in this response). Poll [`GET /v1/audios/{id}`](/api-reference/audios/get-music-job-status) until `status` is `succeeded` — the SFX track is that response's `audio_url` and the input video with the effects mixed in is its `video_url`. Charged per second of the input video's measured duration (whole seconds, 3-second minimum; rate in `GET /v1/models`) on success only. operationId: createAudio_sonilo_video_sfx requestBody: content: application/json: schema: properties: format: default: mp3 description: Output audio format of the SFX track. enum: - mp3 - wav type: string prompt: description: >- Optional direction for the sound design (up to 1000 characters), e.g. "realistic Foley and ambience, no music". type: string video: description: >- The input video (MP4/WebM, up to 360 seconds, 30 MB remote-fetch cap). A public video URL, an uploaded-file URL from POST /v1/uploads, a data URI, or raw base64. Its duration is measured server-side and is the billing basis. type: string required: - video type: object required: true responses: '200': content: application/json: schema: $ref: '#/components/schemas/CreateAudioResponse' description: Job accepted. '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '429': $ref: '#/components/responses/TooManyRequests' components: schemas: CreateAudioResponse: properties: id: description: Opaque job id — use it to poll status. example: aud_a1b2c3d4e5f6 type: string message: type: string model: type: string status: $ref: '#/components/schemas/JobStatus' type: object JobStatus: description: Lifecycle state. `succeeded`/`failed`/`timeout` are terminal. enum: - pending - starting - processing - completing - succeeded - failed - timeout type: string Error: properties: error: properties: code: description: Stable machine-readable code. example: model_not_available type: string message: type: string type: description: Error category. example: invalid_request_error type: string required: - type - code - message type: object required: - error type: object responses: BadRequest: content: application/json: schema: $ref: '#/components/schemas/Error' description: The request was malformed or referenced an unavailable model. Unauthorized: content: application/json: schema: $ref: '#/components/schemas/Error' description: Missing or invalid API key. Forbidden: content: application/json: schema: $ref: '#/components/schemas/Error' description: Authenticated but not permitted (plan gate, ownership, restriction). TooManyRequests: content: application/json: schema: $ref: '#/components/schemas/Error' description: Rate or queue limit reached. Retry after a short delay. securitySchemes: ApiKeyAuth: bearerFormat: bpx_live_* description: 'API key as a bearer token: Authorization: Bearer bpx_live_xxx' scheme: bearer type: http ````